White balance beginner mistakes

[Tom Morrow]

Any video class or course will teach you the importance of white balancing, and teach you the basics of how: You hold a piece of white material in front of the camera and press a button on the camera so that the light falling on that will be considered white to the camera.

But I've worked with a lot of DPs who never go past the basics.

The most important thing to know is that a bad custom white balance is often worse than doing nothing. Even automatic white balance will look better than a poor custom white balance.

The main two mistakes are

-Not doing the light balance under the same light as the subject. If there is a spotlight on the subject then you can't hold the white balance target at the camera, away from the spotlight.

- Not aiming the white balance target. It should be aimed about 45 degrees up, to reflect the sun or whatever the dominant light source is. Theoretically matte surfaces don't need to be aimed but in practice they do. Otherwise aiming the target horizontally at the horizon ends up capturing the color balance of the carpet or ground which might be very different from the light overhead.

The other mistake is to calibrate too often. You should calibrate only when you move to a new scene, not as you move through each little part of a scene. This way everything shot at the same place will look the same. Each calibration introduces a certain amount of error because the camera custom color balance measurement process is never completely consistent.

It is often best to simply keep the setting on daylight default when outdoors, and tungsten when using tungsten lighting. There is no need to do a custom balance when you are sure your light is either the sun or a 3200k bulb, and in fact the presets will be more accurate because you eliminate measurement error.

In the old days when tube cameras had very small latitude in the color space, it made sense to do lots of white balancing in every situation to avoid the color shifts that come from exceeding the dynamic range of the camera.

But today's DSLRs and pro video cameras have very high dynamic ranges and color gamuts, and may even record raw where the color balance can be changed losslessly after capture. So today color balance is less critical. It's more about avoiding noticeable color cast differences between shots and less about fitting the dynamic range of the camera to the scene as in the past. Lower the number of times you custom balance and you will get better color!

[Jon Fairhurst]

Great advice, Tom. This aligns perfectly with my experience.

I once did a shoot in the snow under somewhat variable clouds. We white balanced too often. The colors in our footage were all over the place. How we aimed the card, which direction we faced, and what was nearby had a huge effect on the result. We would have been much better off with a consistent setting. Sure, there will be a slight green cast when the actor is next to a fir tree, but hey, that's natural looking. Turning the snowscape magenta to compensate for the local green on the actor is not natural at all.

I'm now a big fan of keeping it simple and enjoying some color cast on the actor. In fact, I really like using a tungsten fill and key with a partial blue gel on the hairlight or a second key to imply a window in the scene. When shooting around a TV, I'll gel the key to blue, use a dim tungsten fill, and shoot tungsten in the camera to give that blue TV look. On the other hand, shoot daylight, cloudy, or shade (blue) during sunset to highlight the orange and red hues at dusk. A custom white balance is the perfect way to ruin a sunset shot!

[Al Gardner]

Tom,
This might be crazy but every time I change scenes or lighting I actually FILM the white balance card.

That way the editor can use it if he or she needs it.

[Garrett Low]

Tom, from my experience and from what I've been taught, you should not aim the card up at the light. This will give you just as much of a false reading as you are now just capturing the reflection of the sky, ceiling or whatever is above the subject. You also will most likely not get a correct reading because your expose will be off. One of the most important things to do before taking any white balance reading is to set your exposure. Many inexperienced camera ops do not do this.

Also, there are a number of things to consider about which lights to have on when you do your white balancing. To start with you should balance without any back lighting or hair lights. any lights with gels should not be on when balancing unless the gels are being used to correct for differences in the instruments color temp (i.e. using CTB on Tungstens to try to match daylight).

Whether you do another balance when you move the camera depends on a number of factors. But, many times you have to adjust lights when you move the camera so that will often cause a shift thATe could require you to rebalance. It really is a matter of experience to know when you should rebalance.

For sunlight, it can have a huge variation in color temperature depending on the conditions and time of day. Sunrise or sunset can be down at 2000K. In the shade it can be up around 8000K. Overcast days the color temp can be around 6000K in the sun. So there is a lot to think about. Again, it is important to understand what look you are trying to achieve and understand how the specific conditions can affect your color temp.

Al Gardner, your practice of capturing a few seconds of the white card for each scene is a great practice An even better practice would be to shoot a color card like this one:

http://www.bhphotovideo.com/c/product/465286-REG/X_Rite_MSCCC_Original_ColorChecker_Card.html
Your colorist will thank you as it will give them a reference so they have a good starting point when they go to grade your footage.

[Al Gardner]

Garret,
Nice tip. Thanks.

[Tom Morrow]

Jon,

Yes, yes, yes to seeing color casts! They are part of reality and trying to correct for them ruins the background.

I suppose white balancing is a bit like the old zone system... very important to do while you are learning, but rarely done in practice by experts. This is why video classes teach you to custom-white balance up the wazoo: they just want to accelerate your learning of how white balance works. Once you've learned that the advanced course should cover using presets which is best in the majority of situations, as Garrett says.

Garrett I hadn't read your comments here about the angle of the white card when I responded in another thread, but perhaps this is a better thread to discuss angle.

Tom, from my experience and from what I've been taught, you should not aim the card up at the light. This will give you just as much of a false reading as you are now just capturing the reflection of the sky, ceiling or whatever is above the subject.

What I'm getting at is primary illumination versus casts. I aim my card as if I am holding a mirror at subject position reflecting the main light into the camera. This way I get the "reflection of the sky, ceiling, or whatever is above the subject" if that is where the main light that I want to neutralize is coming from. Are you arguing that the color casts from the environment (e.g. from the green leaves in John's example) should take more precedence in the reading and if so why?

[Paul R Johnson]

I'm probably the awkward one, in that I always hold the card parallel with the front of the lens hood. My reasoning is that this will present the same angle to the light source as the subject will. I totally understand the idea behind non-parallel card orientation, and why - BUT - unless your subject aligns their face with the same plane, then the colour balance will be less accurate, when the revert to the normal. If moving the card away from parallel shifts towards blue, then your WB will be incorrect when the subject reverts to the warmer position. That's how my own practice works. No idea if it's considered right or wrong, but it works for me. Card always parallel to the lens hood.

[Chris Medico]

Regardless of the method you choose to use for doing white balance during the shoot I recommend that you roll 10-20sec on the balance card to help in post.

[John Nantz]

After checking out the Lastolite web page Lastolite, Manufacturer of Greycards for Colour Correction and Exposure Control. with regard to their EzyBalance "card", I happened to click on the small print at the bottom of the page: "Instructions". I know, I know, this is un-male to do (my wife tells me) but I did it. Maybe it was out of boredom or constant harassing to "Read the Instructions!", I don't know. Anyway, I did it.

Originally Posted by Paul R Johnson

I'm probably the awkward one, in that I always hold the card parallel with the front of the lens hood.

Lo and behold, there is a diagram in step 2a that gives their suggestion on how to hold the Ezybalance and it is vertical and in front of the lens. "Position Ezybalance so that there is no direct light on it....". So, for Paul, you aren't alone. At least in this situation the Lastolite people suggest the same technique.

And, I might add, you didn't even mention if you read their Instructions!!! Way to go!

[Garrett Low]

John, reading instructions are manly. Ever try to operate a RED without reading the damn manual. LOL.

Anyway. I generally have the balance card straight on to the camera lens, and I don't think my Lastolite came with any instructions, maybe it did and I just automatically threw them away.

[Jon Fairhurst]

Not long ago, I was shooting our local "science fair". One of the demos was in a basement room with about half of ceiling lights with a bluish cast and the other half with an orange cast. Neither the tubes nor diffusers matched. Many of the diffusers were old and yellowed. As the presenters moved around, so did the color of their lighting.

I ended up going for about 3800K. Skin went a little red, but not extremely so. The key was to reduce saturation in post.

It just goes to show that there's not always an ideal white balance solution.

BTW, we shot some RAW greenscreen this weekend using a hacked 5D2. The setup was faster and easier than when shooting normal greenscreen with the 5D2. In the past, we'd boost the chroma to really get the screen to sing - but not clip. In post, we'd key and then bring down the skin tones. The keys were pretty good but it took a lot of work to balance things between maximum signal for clean keys and wanting headroom. Add color balance to this, and it's a real balancing act.

With RAW, things were much simpler - expose within a stop of the ceiling and shoot.

What we learned is that shooting RAW isn't just about putting off creative decisions until post. For us, it was about not dicking around with the camera while the rest of the crew is ready to go. We simply set up the lights to match the scene, balanced key and fill, set exposure and shot.

Best of all, the keys were killer. Using Keylight, we could get a passable comp over white with one click. Hair and motion blur were problem free.

Of course, one still needs to understand color temps when lighting and when coloring in post. And when you're not doing narrative work or when you need a fast turnaround, RAW isn't the most practical option. But, if you plan post work and can handle ingest and storage, it can make the on-set experience quite nice - even with hack firmware!

[Tom Morrow]

Originally Posted by John Nantz

Lo and behold, there is a diagram in step 2a that gives their suggestion on how to hold the Ezybalance and it is vertical and in front of the lens. "Position Ezybalance so that there is no direct light on it....". So, for Paul, you aren't alone. At least in this situation the Lastolite people suggest the same technique.

Frankly that instruction (in 2a of http://www.lastolite.com/pdfs/Ezybal...structions.pdf ) to not have any direct light on the target makes no sense at all to me. Of course you want your target illuminated by the same light that your subject is in, whether that light is direct or not.

I will also note that those directions have a graphic in 2a reminding you not to angle it down, which I think we can all agree is a good idea.

Heads are not perfectly symmetrical; looking at a face you see more surfaces facing upward (including the top of the head) and fewer surfaces facing downward (you don't see the bottom of your head because it's inside your neck). Most importantly the color casts from below are more shadowed and mentally filtered out if the object that is causing the cast is in frame (e.g. the green leaves in a forest). This is part of why I prefer to angle the target up in mixed light.

[John Nantz]

Tom - that's a good reply and I see where you're coming from. To take a measurement without any direct light somehow doesn't seem right and I'm having some trouble trying to make sense of it. It makes a lot more sense to have the card illuminated with the same light as the subject.

Maybe I think this because takes me back to my 35mm days and my Weston Master V light meter where one would take a reading off the subject or your hand, or whatever, depending on what one wanted in the picture.

Measuring lighting and correcting for it in video is a lot different than it was with using film. With film it was basically a light meter and screw-in color correction filters. And I still have a a bunch of them.

Correcting for mixed light in post is a lot of work so trying to get good camera settings in the beginning would be helpful.

[Josh Bass]

Tom beat me to it, but yeah, i always figured the slight upward angling of the card or whatever youre using for balance was to (very roughly) simulate the curvature of the (likely) human subject you were about to shoot. I guess the ideal would be to carry around one of those foam heads used to hang wigs. Impractical maybe but at least then you could be "that cool videographer who carries a head around."

And of course you want to hit it with direct light! Thats what youre trying to neutralize!

[Paul R Johnson]

Instructions? Never read them! If I have to read instructions, then the product was poorly designed. Sure - for the clever functions you need to look things up but for getting something up and running, needing a manual to me means not enough care and attention.

I'm old enough to remember how important white balance actually was with tube cameras (my wife's green wedding dress shows how bad it used to be) but nowadays I have to own up to using the presets based on what lighting I see. I work in theatres mainly, and colour balance depends on the lighting type. Annoyingly it's often a mix of tungsten and discharge, and even worse, more than one kind of discharge. Last week in a project I had in one section, 4 pre-focussed open white specials on a band - one for each mic position, 8 discharge movers of one colour white, and 4 of a bluer one. Add in two followspots in yet another white and choosing the right white is better done by presets. My selection is done by looking at the stage with all these things on - and to my eye, the tungsten ones are very yellow, and some moving lights very blue. Some movers actually have conversion filters built in - but you lose light, so if they are going to spend their on-time in mainly red, it probably doesn't matter. My main selection criteria is faces need to look 'right' - other than that, presets work better for me, and any weird colour casts can be sorted in post. I use identical cameras, so using the presets gives me a constant white balance, even if white isn't quite white!

EDIT - I'd not want to use anything but a card - a head would have all sorts of weird artefacts - colours under eyebrows, over the lips and to the side of the nose. I have no idea what a camera auto balance would make of a white image with different colours on it!